With the development of large-scale integrated circuit technology, MEMS, wireless communications and optical technology, capsule endoscope has been used as an effective way for diagnosis for intestinal diseases. M2A produced by Given Imaging, a company in Israel, Endo Capsule researched and developed by Olympus Company in Japan, and products marketed under a Chinese company, Jinshan Science and Technology, all have taken significant market shares in the capsule endoscope marketplace. The current available wireless capsules adopted in the medical field are carried by peristalsis through a human digestive tract, as a result the movement speed, movement direction and capsule location is random, which makes it difficult for medical doctors to collect the relevant information for intestinal tract diagnosis.
If positioning and controlling a capsule endoscope in vivo cannot be achieved, navigating it through a human GI track for traversal intestinal diagnosis/examination face multiple issues. Current existing capsule endoscopes mainly rely on peristalsis and organs contraction to accomplish the capsule movement along a GI track in vivo. Such movement is not only slow, leading to low detection efficiency and potential dead zones in the examination, but also makes examination or operation in specific disease region impossible, as the movement based on peristalsis cannot move the capsule endoscope back and forth to a precise target location for a stable examination or operation, and such movement does not allow control of movement speed and direction, and the posture.
Chinese domestic Jinshan Group has manually controlled an external magnet to accomplish the position or navigation of a capsule endoscope in GI track. The manual control is low cost, but is less precise than a mechanical robot thus less favorable in a routine testing, which prefers artificial intelligence. Furthermore, several scientific research institutions have demonstrated controlling a magnetic capsule endoscope by a strip shaped external magnet. This method is quick and can precisely place the capsule in a direct route, however, because human GI track is not straight but very snaky, it is very difficult to carry out actual positioning of capsule endoscope using such linear magnet in practical clinical setting.
US patent applications Ser. Nos. US20070221233, 20100268026, 20110054255, and 20110184235 disclosed a floating or suspended capsule. As described in these patent applications, a magnetic capsule is suspended by a surrounding liquid, which requires the density of the capsule to be less than the liquid. In clinical practice, since the most commonly used liquid is water, the weight of such floated capsule is limited to be under 3 g. If a capsule is equipped with a permanent magnetic dipole to achieve better positioning, the weight of the capsule unfortunately easily go over 3 g. For a capsule endoscope whose density is more than water and perhaps weight is over 3 g, how to realize stable suspension has not been disclosed.